1. Field of the Invention
The present invention relates to a modified powder excellent in water resistance, cleansability, and ultraviolet protection effect and to a cosmetic composition using the same, and in particular, relates to a sunscreen cosmetic composition containing an inorganic ultraviolet scattering agent.
2. Prior Art
In the past, the functions such as coloring the skin, hiding pigmented spots and freckles, and protecting the skin from ultraviolet light were provided by blending powder into cosmetic compositions. In recent years, in order to achieve longer-lasting makeup, powders, the surface of which is hydrophobized, are frequently used (refer to Japanese Unexamined Patent Publication H08-208425 and Japanese Unexamined Patent Publication H08-059448).
Middle wavelength ultraviolet light (290-320 nm) in the sunlight is known to cause the formation of erythema and blisters, an increase in melanogenesis, pigmentation, etc.
In addition, long wavelength ultraviolet light (320-400 nm) has an immediate pigment darkening effect, which darkens the skin immediately after exposure. Its energy reaches the dermis; therefore, the vascular wall and the elastic fibers of the connective tissue are also affected. The effect of the middle to long wavelength ultraviolet light promotes the aging of the skin, and it is considered to be part of the reason for pigmented spots, freckles, wrinkles, and skin cancer.
In order to protect the skin from ultraviolet light, titanium dioxide powder, zinc oxide powder, etc. have been used as ultraviolet scattering agents. In recent years, in order to increase water resistance, ultraviolet scattering agents, the surface of which is hydrophobized, are frequently used.
For example, sunscreen cosmetic compositions containing fine titanium dioxide particles, the surface of which is treated with metallic soap, are publicly known (refer to Japanese Unexamined Patent Publication H08-208425).
However, the cosmetic compositions containing a powder, the surface of which is hydrophobized, often remains on the skin, after cleansing, because the makeup is long-lasting.
In particular, it is difficult to remove, with a normal cleanser, sunscreen cosmetic compositions that contain, as an ultraviolet scattering agent, a powder, the surface of which is hydrophobized. This is because of the good water resistance of the cosmetic compositions, and it is recommended to use a special cleanser. As a result, such sunscreen cosmetic compositions sometimes gave consumers an impression that they are unsuitable for everyday use.
The objects of the present invention are to provide new powders with excellent water resistance, easy removal with a normal cleanser, and the ultraviolet protection effect, to provide cosmetic compositions containing the new powder, and in particular to provide sunscreen cosmetic compositions containing an ultraviolet scattering agent.